The present invention relates generally to a portable telephone, and more particularly, to a circuit and method for indicating that a portable telephone has been lost by its owner.
Since a portable telephone is typically moved from place to place with its owner, it can easily become lost or misplaced. If the lost telephone winds up in the hands of an unscrupulous finder, unauthorized long distance fees can be charged to the owner. Therefore, the economic loss involved when a portable telephone is lost may be substantially greater than the cost of the telephone itself
Moreover, if a person calls the lost telephone in an effort to contact the owner, the finder may obtain information that is private to the owner, and can possibly make statements that are harmful to the owner's interests. The main reason why this problem exists is because, conventionally, there has been no way for the finder to easily contact the owner, even if the finder is gracious enough to want to return the telephone to its rightful owner.
One notable effort directed towards the general concept of locating a particular portable telephone is the Vehicle Locating And Communicating Method And Apparatus Using Cellular Telephone Network, U.S. Pat. No. 5,299,132 issued to Wortham. In Wortham '132, a method is provided by which one can locate and communicate with a vehicle having a mobile cellular unit installed therein. A microprocessor periodically instructs the mobile cellular unit to initiate a call to a host controller, and upon receipt of transmitting instructions from the host controller, the mobile cellular unit transmits information regarding its location to the host controller. While this type of effort is useful as an attempt to provide some type of scheme for determining where a particular mobile cellular unit and the corresponding vehicle are located, I have noticed that this scheme prevents individuals from effectively using the mobile cellular unit if the unit should become lost. Accordingly, I have found there exists a strong need for a portable telephone having features that enhance the ability of the telephone owner to recover the telephone when lost, and also to prevent a vicious finder from exploiting the interests of the owner.